The US Supreme Court has granted review to same-sex marriage cases from four states.

The country’s top court announced it would review a ruling from the Sixth Circuit Court of Appeals which upheld same-sex marriage bans in Kentucky, Michigan, Ohio and Tennessee.

The case is expected to be a defining moment in the battle for same-sex marriage in the United States – and could even see same-sex marriage in all 50 states by the end of the year.

The Supreme Court has declined to intervene in the issue in the past when initial rulings were in favour of equality, but the Sixth Circuit Court of Appeals ruled against same-sex marriage in the four states.

The Justices wrote today: “The petition for writs of certiorari are granted.

“The cases are consolidated and the petitions of certiorari are granted limited to the following questions:

“1. Does the Fourteenth Amendment require a state to license a marriage between two people of the same sex?

“2. Does the Fourteenth Amendment require a state to recognise a marriage between two people of the same sex when their marriage was lawfully licensed and performed out-of-state?”

The direct phrasing of the questioning suggests the court is seeking to make a more conclusive ruling than that in 2013’s United States Vs Windsor, which partially repealed the federal Defense of Marriage Act but ducked the wider issue of a right to same-sex marriage.

The deadline for briefs has been set for February 27, with reply briefs due by April 17 – signalling a possible final ruling projected for June.

Evan Wolfson of Freedom to Marry said: “The Supreme Court’s decision today begins what we hope will be the last chapter in our campaign to win marriage nationwide – and it’s time.

“Freedom to Marry’s national strategy has been to build a critical mass of marriage states and critical mass of support for ending marriage discrimination, and after a long journey and much debate, America is ready for the freedom to marry.

“But couples are still discriminated against in 14 states, and the patchwork of discrimination harms families and businesses throughout the country.

“We will keep working hard to underscore the urgency of the Supreme Court’s bringing the country to national resolution, so that by June, all Americans share in the freedom to marry and our country stands on the right side of history.”

Same-sex marriage is currently legal in 36 US states, and banned in 14.